Soldering iron temperature control stand



July 8, 1941. H. w. BIRK SOLDERING IRON TEMPERATURE CONTROL STAND Filed July 15, 1939 2 Sheets-Sheet 1 1954mm) I/511 211 g /fi p July 8, 1941. 4 H. w. BIRK SOLDERING IRON TEMPERATURE CONTROL STAND Filed July 15, 1939 2 Sheets-Sheet 2 HAROLD WEIR/r Patented July 8, 1941 2,248,486 v SOLDERING IRON TEMPERATURE CONTROL STAND Harold W. Birk, East Hartford, Conn., assignor to The Hart Manufacturing Company, Hartford, Conn., a corporation or Connecticut Application July 15, 1939, Serial No. 284,808

1 Claim.

The present invention relates to a stand for supporting an electricsoldering iron, and more particularly to an improved stand of the type wherein the control of the flow of current through the heating coil of the iron is controlled by means located within the stand.

An object of the invention is an improved stand of the type having an electric circuit therein, into which circuit the heating coil of the iron may be connected, and wherein there is provided within the stand thermostatic means responsive to heat radiated from the iron for controlling the flow of current to the heating coil of the iron.

A still further object is a stand of this type wherein there may be incorporated suitable signal means for keeping the operator informed at A all times as to the operating condition of both the stand and the iron.

A still further object is a stand of this type having various features of novelty and advantage and which is particularly characterized by its extreme simplicity in construction, economy of manufacture, and efiflciency of operation.

Other objects will be 'in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination or elements, and arrangement of parts which will be exemplifled in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claim.

In the accompanying drawings:

Figure 1 is a sectional side view of the stand showing an iron resting thereon;

Fig. 2 is a perspective view of the stand;

Fig. 3 is a bottom view of the stand with the bottom plate broken away to show the interior construction thereof; and

Fig. s is a diagrammatic view of the wiring circuit within the stand.

Referring to the drawings, the letter A designates the type of soldering iron commonly employed in industrial plants; the iron having a handle iii, shank l2, and a replaceable soldering iron tip It. Disposed around the shank l2 and inwardly from the tip is a heating coil l6 suitably enclosed within a housing E8 of greater leads 20 to a two-pole plug 22 adapted to be plugged into a suitable outlet connecting to a source of electrical energy.

In accordance with the present invention, the

iron A is adapted to be supported on a stand B and the heating coil of the iron A connected into a circuit arranged within the stand B and connecting to a source of electrical energy. The stand-B also has therein thermostatic means responsive to heat radiated from the heating coil of the iron and adapted to make and break the circuit to control the flow of current through the heating coil of the iron. There is further arranged wlthin the circuit of the stand signal lights for indicating whether or'not the iron is up to proper temperature; the detailed arrangement of the thermo-responsive element and signal lights being hereinafter described in full.

The stand B is preferably cast in one piece from a suitable fire resistant material or formed from such material as "Al-moo iron or porcelain; and comprises a box-like structure having a high forward wall 24, a low rear wall 28, side walls 28 and 30, and a top plate or wall 42 inclining downwardly at an angle of approximately ten degrees from the forward wall 24 to the rear wall 26.

The side and end walls have depending portions adjacent each corner thereof to provide supporting feet 3 for spacing the support above the surface upon which it rests to allow air circulation thereunder. If desired, the bottom of the stand may be closed by a removable bottom plate 36 adapted to be positioned on a flange it and secured in place by screws 40 extending through aligned openings in the bottom plate and flange; the bottom plate also having a plurality of openings 48 therein to allow air circulation into the base. r

In order to properly position the iron A on the stand B, the central portion of the upper iace of top wall 32 is hollowed out to provide a trough 42 having a transverse curvature with a radius similar to the housing l8 of the heating coil it and extending longitudinally from approximately the end wall 24 to an upwardly directing shoulder 44 spaced forwardly of end wall 26. Extending longitudinally between shoulder t4 and end wall 28, the top wall is further hollowed out to provide a groove 45 having a transverse curvature with a radius similar to the tip M of the iron and arranged with its center line in alignment with the center line of trough 42, whereby the contour of the top plate substantially conforms to that of the iron.

The top plate 32 of the stand, which is of appreciable thickness, also has cut therethrough an opening which extends longitudinally of the trough 12 and in alignment with the center thereof to provide a flue 60. There is arranged in the due 60 a thermoresponsive element 52 arranged in the circuit within the base and adapted to control the flow of current therethrough. he clearly indicated, the element 52 is placed slightly below the surface of the top plate. and in order to properly protect the element a cover plate may be placed over the flue and provided with a plurality of openings 84 therethrough; the cover plate in the embodiment shown. being integral with the top plate 32.

With the thermo-responsive element so arranged, when the iron is removed from the stand the element is subjected to acurrent of coolair passing through the flue, which ourassists in radiating heat from the element, causing same to cool rapidly, whereupon it will move to closed position and speed the on cycle. However, when the iron is placed on the stand, the inclined top wall 32, trough 42, shoulder 44, and groove 35 thereof cooperate with the coil housing iii of the iron, the stop 15, and iron tip id to guide the iron into position, whereby the coil housing overlies and closes the flue to subject the th rmo-responsive element to radiant heat therefrom. By making the thermo-responsive element active torthe radiant heat of the coil adjacent the secured end of the tip, rather than directly responsible to the heat of the tip itself, the heating element will not burn out even if the tip is loose or the heat is improperly conducted thereto, thus assuring a longer life for the iron and also enabling the use of a lower resistance heating coil, with the resultant advantage that more rapid heating of the iron is obtained.

The thermostatic or thermo-responsive element 68 comprises a U-shaped strip of bimetallic metal having a pair of legs 66 and 68 and is so arranged that the ends of the legs will tend to separate when cooled and move towards one another when heated. The outer end of a leg 88 of the element is fixed, as by riveting, to a metallic strip it having an upper portion secured to the side wall of the flue and a lower portion depending below the flue and having a screw 74 threaded therein for electrically connecting the strip into the electric circuit within the base. If the stand is made of a conducting material, the strip l6 may, as in the embodiment shown, be riveted to the vertical leg H of a right angle bracket 33 of insulating material; the horizontal leg of the bracket being positioned against the under surface of the top plate and secured thereto by a crew F8.

The thermoeresponsive element 50 controls suitable switch means for making and breaking the circuit to the iron coils, said means comprising a contact 59 carried on the free end of leg 68 and adapted to be moved thereby into and out of engagement with a relatively fixed contact 82. The contact 82 is carried on the end of an elongated stud 8 t threadably mounted in ametal plate 88 having its upper portion mounted to the side of the flue and its lower portion depending below the fiue and having a screw 90 threaded therein for electrically connecting the strip and contact 80 to a lead of the electric circuit. The stud 8 extends through a suitable opening in the side wall of the stand, and the outer end is slotted to receive the bit of a screw driver, whereby it may be adjusted to move the contact 82 toward or away from contact on the free end of the theme-responsive element, thus making it possible to accurately adjust the thermo-responsive element within the stand to maintain the desired iron temperature. In this way, it is possible to maintain the iron at a low temperature, it it is desirable to use it for wax melting or the like, or at high temperatures for electric branding irons.

the embodiment shown, the metal plate 88 is riveted to a suitable piece of insulating material 92 secured to the side of the flue by screws .34, and the stud 84 extends through a sleeve of insulating material 85 positioned in the opening in the side of the stand, thus completely insulating same from the stand.

The thermo-responsive element 60 has in series therewith an electrical outlet 48 positioned in side wall 28 of the stand and adapted to receive the plug 22 oi the iron B. The outer end of the outlet is provided with a flange 49 of greater outside diameter than the opening through the side wall, and the inner end is provided with a split ring 5! adapted to be secured around the outer circumference thereof and abut the inner surface of the wall 28 and secure the outlet in position. If the base is made of porcelain or like material, the outlet may be formed therein with the metal parts secured in the usual manner.

With this arrangement, when the iron is mounted on the stand and the heating coil is in circuit with the thermo-responsive element, the radiant heat from the coil will cause the thermoresponsive element (which, when cool, normally closes the circuit) to become heated and open contacts 80 and 82 and break the flow of current to the heating coil of the iron; the contact 82 being so adjusted that this occurs when the iron has reached a predetermined temperature. This is of particular advantage where intermittent use of the iron is made, for by discontinuing the flow of current through the coil whenever a predetermined temperature therein has been reached, a considerable amount of energy is conserved, while always maintaining the iron at a proper temperature for immediate use. This also serves to preserve the life of the heating element by removing the possibility of over-heating, and by maintaining the correct temperature, oxidation of the tip does not take place, thus serving to keep the iron tinned.

There is also arranged in circuit with the thermo-responsive element 60 and the heating coil outlet suitable visible means comprising a pair of pilot lights adapted to indicate to the operator when current is passing through the heating coil or when the current has been cut off after the iron has reached a predetermined temperature, and also for indicating" when the stand is connected to a source of electric supply even though no iron be connected thereto. These means comprise a pair of bulb-receiving sockets 55 and 51 arranged in suitable openings at the intersection of the end wall 24 and top plate 32; the socket 55 being closed with a red lens and socket 5'! with a green lens. As indicated, the sockets are arranged atv an angle of approximately forty-five degrees to the horizontal, and the end of the stand may be rounded off at the intersection of the top and end wall to enable the lights to be/visible through a greater angular range.

As indicated in Fig. 4, the red pilot light 55 is connected in parallel with the iron heating pared to the light 51, the current will be shunted though the element to the light 55 and the heating coil 16 of the iron, whereupon the light 55 will glow and indicate that the iron is being heated.

Inasmuch as the housing l8 of the heating coil of the iron overlies and closes the flue 62, the heat radiated from the iron will pass through the top plate openings 32 and heat the thermoresponsive element 60. With the contact 82 properly adjusted relative to contact 80, when the iron has heated to a predetermined desired temperature the contacts will be separated, whereupon the breaking of the contacts the light 51 will then be placed in series with the parallel arrangement of the light 55 and the heating coil iii of the iron. When this occurs, the light 51 will glow, butas the resistance thereof is relatively high, the drop in current therethrough will be such that' the amount of current passing through light 55 will beinsufiicient to cause it to glow and the temperature of the heating coil of the iron IE will not be materially afiected.

Upon removing the iron from the stand, a current of air will immediately flow through the openings 4| in the bottom plate 32 and the flue 60 in the top plate 32, whereupon a rapid cooling of the thermo-responsive element 60 will result, causing it to close the contacts 80 and 82, shunting out the light 51, and again causing the light 55 to glow and the coil of the iron to start heating.

If the heating coil of the iron A should become disconnected from the stand, the thermoresponsive element will close, and if the stand is not disconnected from the source of electrical energy, the light 55 (as in Figure 4) will be on with normal brilliancy.

With the foregoing arrangement of signal lights, the operator will at all times be kept informed as to the condition of the iron and likewise will always know whether or not the stand A is connected to a source of electrical energy, and thus the possibility of inadvertently leaving the stand connected for long periods of time is eliminated. Obviously, if the signal lights are not included, inasmuch as they are in parallel with the circuit, the circuit will continue to function to control the flow of current through the coil whenever the iron is placed upon or removed from the stand.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claim is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

A stand for an electrically heated soldering iron, said stand having a top wall, end walls and side walls, one of said end walls being higher than the other, whereby said top wall is arranged on an incline, said top wall having a trough therein extending longitudinally from said high end wall and terminating at a shoulder spaced inwardly from said low end wall in a groove extending longitudinally from said shoulder to said low end wall and in alignment with the center of said trough, said incline, trough and groove cooperating to guide and position an iron thereon, said top plate further provided with a fine extending therethrough and in central alignment with said trough, thermo-responsive switch means positioned in said flue and adapted to be responsive to heat radiant from an iron resetting in said trough, an electric outlet in one of said side walls and into which an iron may be connected and a circuit extending through said stand and connecting said thermoresponslve switch means in said outlet.

HAROLD W. BIRK. 

